Example of forgone maintenance... (archive)

The complete automotive resource for buyers, sellers, and owners like you.

In Reply to: Re: Must like Vegas... posted by Matt Evans on February 23, 2001 at 09:42:52:

Future purchasers, this is a perfect example of the scary stuff that you may find in your next M5. How would a mechanic or trained eye ever find it. Not until the engine destroys itself one sunny Saturday afternoon. Sorry to go off, but this is exactly why people don't buy these cars unless there's really good evidence that the PO's were able to afford the maintenance.

C'mon Matt, sell it or do it right but don't ruin it. It sounds like a great car in a make or break situation.

Its not supposed to vibrate all that much with 325ft pounds on it. I had it hack/fixed once (no locking compounds at all, same harmonic balancer, crank nut put on with impact gun (shop didn=t know better)). It worked for about 6 weeks, and there wasn=t a problem until the crank nut was completelz gone.

I went the route of trying to fix it right. Thats close to a grand in parts and a couple grand in labour, assuming i can find someone willing ot do it (my normal mechanic wont, he thinks some other part of the motor will blow up once this is fixed). i live in an apartment and have no garage, so where and when i can do multiday repairs is pretty limited...(frown).. so if my options are a few dollars for jbweld or a few thousand for all new crank parts and or a new motor, i think ill give the jb weld avenue a try...

because, no offense, but you'll get better odds at a craps table. No polymer-based material can withstand the friction and forces of the crank hub oscillation of a 286hp 7k rpm engine. Remember, it initially fatigued and *welded* the hardened metal of the hub. Loctite will not stand up to this.

Even worse, if it does work say for a day, or maybe even a month, when the loctite does gives-up you're very likely to do some serious damage to the tune of $10k, not $1k. Remember, if you sell it after the loctite fix, and the engine destroys itself yet you didn't disclose the problem, you're liable to the new owner for the repair.

I'd suggest giving the M5 its due and fixing it correctly so you or the next owner doesn't have to re-do it shortly. Pulling the engine and replacing the crank is not that difficult. You can leave the head, pistons, etc. in place and just surgically graft-in the new crank with a fresh set of bearings. Email me if you need details.

are you sure you wanna risk holding on a crank hub at 6,000 rpm with locktite? stand clear.

No, i want to use jbweld to hold the key in place (it just sits normally), loctite anti-shear compound to hold the crankhub in place (it just sits normall) and threadlocker to help hold the crank nut in place (it "just" screws on with 325ft/lbs normally)

If my crank nut hadn't already come off twice and caused metal trading to go on on my crank snout.. then this would be far and away a solution of superior strength. :)

Questions, comments, or problems, please visit the Roadfly help desk.